Temperature-regulation targets that require temperature regulation include but are not limited to a secondary battery storing electric power to run an electric automobile, a hybrid automobile, and the like, electric devices generating heat while in use, and air conditioning of a vehicle interior space. These temperature-regulation targets have an appropriate temperature range to exert furnished functions and an appropriate temperature range to maintain comfort and therefore require a temperature regulation device capable of regulating a temperature within the appropriate temperature range as needed.
Such a temperature regulation device is described in Patent Document 1. The temperature regulation device of Patent Document 1 has an evaporator cooled by a refrigerant supplied from a refrigeration cycle of an air-conditioning device and provided to an air passage in which a vehicle battery is installed, and cools the battery by letting air circulate in the air passage using an air sending device.
Patent Document 2 describes a temperature regulation device using a heat pipe. The temperature regulation device of Patent Document 2 includes a heat pipe heat-absorbing portion provided in close proximity to a side portion of a case storing a battery to absorb heat by flowing a refrigerant internally, a heat pipe heat-releasing portion provided to the outside of an vehicle interior and releasing heat by flowing the refrigerant internally, and a connection portion connecting the heat pipe heat-absorbing portion and the heat pipe heat-releasing portion to let the refrigerant circulate. The heat pipe heat-absorbing portion, the heat pipe heat-releasing portion, and the connection portion together form a heat pipe in which the refrigerant circulates by condensation and evaporation of the refrigerant.
Patent Document 3 describes a temperature regulation device provided with an air-conditioning refrigeration cycle capable of not only heating but also cooling a vehicle interior space. The temperature regulation device of Patent Document 3 switches flows of air by controlling opening and closing positions of multiple dampers and can therefore introduce air heated in a high-pressure side heat exchanger into the vehicle interior space during heating and introducing air cooled in a low-pressure side heat exchanger into the vehicle interior space during cooling.
According to the technique of Patent Document 1, the evaporator to cool the battery is included but no device to heat the battery is included. Hence, the battery cannot be heated and a separate heating device may be required in order not only to heat but also to cool the battery.
According to the technique of Patent Document 2, the battery is cooled by the heat absorbing action of the heat pipe method. Hence, this technique can cool the battery in a case where the battery generates a small amount of heat and required battery cooling performance is several hundred watts or less on such occasions as when the vehicle is parked or traveling in the city. However, this technique may possibly fail to cool the battery sufficiently in a case where the battery generates a large amount of heat and required battery cooling performance is approximately several kilo watts on such occasions as when the vehicle is traveling at a high speed or climbing a hill. In addition, the technique of Patent Document 2 can only cool the battery. Hence, in order not only to heat but also to cool the battery, a separate heating device may be required.
The technique of Patent Document 3 relates to a device used for the air conditioning of the vehicle interior space. When this technique is applied to battery temperature regulation, it becomes necessary to drive a compressor even when required battery cooling performance is low (under low load) on such occasions as when the vehicle is parked or travelling in the city, and noises to the environment may possibly raise a problem. Also, in the device of Patent Document 3, a flow rate of the refrigerant is low under low load and an oil returning state to the compressor may possibly be deteriorated.